Conference netcad::hub_mgnt

1038.0. "DECConcentrator 900 MMF Installation Problem" by LEVERS::IANNARONE () Fri May 27 1994 20:35

    The DECConcentrator 900 Installation manual has an error that may lead
    to  problems when installing the multimode fiber modpmd.  In the
    section of the manual titled "Removing and Installing ModPMDs" there is
    a subsection titled "Install the faceplates".  Within this section is 
    an illustration showing the MMF faceplate and the metal shield. 
    (I don't give a specific page no. because a few different versions of
    the manual have already shipped, and the picture is on different pages)
    The metal shield is pictured upside down relative to the LED holes in
    the faceplate.  If the shield is upside down, the faceplate cannot be
    installed properly.  While this will be fixed in the documentation, I'm
    putting this entry here to help disseminate this information in the
    meantime.  Some installation instructions are shown below:  
    
    The shield should be installed over the fiber optic transceiver after 
    the bezel is installed.  If one lays the concentrator flat and looks at
    the front of the module such that the modpmd leds are on the right side
    of each modpmd, the shield should be installed such that short side of
    the shield is on top, and fits between the fiber optic transceiver and
    the modpmd pc board.  When properly installed, the tabs on the shield 
    should sit flush with the bezel.  If installed upside down, the shield
    will NOT seat properly and the tabs will be about .200 inches off the 
    bezel surface.  If the tabs are NOT flush with the bezel, the faceplate 
    cannot be properly installed.  Anyone attempting to install a MMF modpmd 
    should verify that when the shield is installed, the tabs sit flush on 
    the bezel.  
    
    Future versions of the MMF modpmd will utilize plastic cases for the
    transceiver, and these probably will NOT need the shield at all.  But
    the all-metal case transceivers require the shields for ESD
    protection.